U.S. patent number 5,141,787 [Application Number 07/695,134] was granted by the patent office on 1992-08-25 for air bag.
This patent grant is currently assigned to Nippon Seiki K.K.. Invention is credited to Kazuo Yamamoto.
United States Patent |
5,141,787 |
Yamamoto |
August 25, 1992 |
Air bag
Abstract
An air bag has a pair of circular fabrics overlapping one upon
the other with their marginal portions being stitched by crossing a
sewing thread on the side of their edges to form a seam so that the
seam is showing. The marginal end portions can be neatly enwrapped
by the seam, not only providing the air bag with an unimpaired
appearance but also making it compact when folded.
Inventors: |
Yamamoto; Kazuo (Kanagawa,
JP) |
Assignee: |
Nippon Seiki K.K. (Tokyo,
JP)
|
Family
ID: |
12974883 |
Appl.
No.: |
07/695,134 |
Filed: |
May 3, 1991 |
Foreign Application Priority Data
|
|
|
|
|
May 28, 1990 [JP] |
|
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2-54588[U] |
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Current U.S.
Class: |
428/35.5;
112/440; 112/441; 112/475.26; 280/728.3; 428/102; 428/192;
428/35.4; 428/36.1; 428/64.1 |
Current CPC
Class: |
B60R
21/235 (20130101); B60R 2021/23576 (20130101); Y10T
428/1362 (20150115); Y10T 428/1341 (20150115); Y10T
428/21 (20150115); Y10T 428/24033 (20150115); Y10T
428/24777 (20150115); Y10T 428/1345 (20150115) |
Current International
Class: |
B60R
21/16 (20060101); B65D 030/10 (); B60R
021/00 () |
Field of
Search: |
;280/727,728,731,734,732,730 ;383/3
;428/35.2,35.4,35.5,35.7,36.1,64,65,102,192
;112/440,441,262.1,269.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Robinson; Ellis P.
Assistant Examiner: Dye; Rena L.
Attorney, Agent or Firm: Sughrue, Mion, Zinn Macpeak &
Seas
Claims
What is claimed is:
1. An air bag, comprising:
a pair of circular fabrics overlapping one another to form
overlapping marginal portions having peripheral edge portions, said
overlapping marginal portions being stitched by crossing a sewing
thread in a radical direction of said fabrics over said peripheral
edge portions to form a seam, said seam being exposed.
2. An air bag according to claim 1, wherein a first piece of said
sewing thread is arranged on said first fabric and a second piece
of said sewing thread is arranged on said second fabric, and said
first and second pieces of said sewing thread are interlaced at
said peripheral edge portions where said marginal portions
meet.
3. An air bag according to claim 2, further comprising:
a catching thread for holding said first and second pieces of said
sewing thread at a position inward from said peripheral edge
portions.
4. An air bag according to claim 1, wherein said sewing thread
comprises a single piece of sewing thread for stitching said
peripheral edge portions, said single piece of said sewing thread
being alternately spread over both said first fabric and said
second fabric.
5. An air bag according to claim 4, further comprising:
a catching thread for holding said single piece of said sewing
thread at a position inward from said peripheral edge portions.
6. An air bag, comprising:
a pair of circular fabrics overlapping one another to form
overlapping marginal portions having peripheral edge portions, said
overlapping marginal portions being folded inwardly, said inwardly
folded marginal portions being stitched by crossing a sewing thread
in a radical direction of said fabrics over said peripheral edge
portions to form a seam, said seam being exposed.
7. An air bag according to claim 6, wherein a first piece of said
sewing thread is arranged on said first fabric and a second piece
of said sewing thread is arranged on said second fabric, and said
first and second pieces of said sewing thread are interlaced at the
peripheral edge portions.
8. An air bag according to claim 7, further comprising:
a catching thread for holding said first and second pieces of said
sewing thread at a position inward from said peripheral edge
portions.
9. An air bag according to claim 6, wherein said sewing thread
comprises a single piece of sewing thread for stitching said
peripheral edge portions, said single pieces of said sewing thread
being alternately spread over both said first fabric and said
second fabric.
10. An air bag according to claim 9, further comprising:
a catching thread for holding said single piece of said sewing
thread at a position inward from said peripheral edge portions.
11. A method of sewing an air bag, said method comprising the steps
of:
overlapping a pair of circular fabrics; and
stitching overlapping marginal portions having peripheral edge
portions of said pair of fabrics by crossing a sewing thread in a
radical direction of said fabrics over said peripheral edge
portions to form a seam while said pair of circular fabrics is cut,
said seam being exposed.
12. An air bag according to claim 3, wherein said circular fabrics
comprise an elastic material, each of said circular fabrics having
a surface coated with rubber.
13. An air bag according to claim 3, wherein said circular fabrics
comprise an elastic material, each of said circular fabrics having
a surface coated with resin.
14. An air bag according to claim 3, wherein one of said circular
fabrics has an opening formed therein.
15. An air bag according to claim 8, wherein said circular fabrics
comprise an elastic material, each of said circular fabrics having
a surface coated with rubber.
16. An air bag according to claim 8, wherein said circular fabrics
comprise an elastic material, each of said circular fabrics having
a surface coated with resin.
17. An air bag according to claim 8, wherein one of said circular
fabrics has an opening formed therein.
Description
BACKGROUND OF THE INVENTION
The invention relates to air bags that are used to protect drivers
in the event of a collision between motor vehicles.
As shown in FIG. 8, an air bag B is mounted on a hub body of a
steering wheel S of a motor vehicle, and this air bag B is inflated
by a pressurized gas that will be charged thereinto in the event of
a collision of the motor vehicle so that a driver D can be
protected.
A conventional method of sewing such an air bag comprises the steps
of: either overlapping a pair of circular fabrics one upon the
other; sewing the overlapping marginal portions in two lines of
stitching; and reversing the right and wrong sides so that the two
lines of stitching at the marginal end portions are hidden in the
inside of the air bag; or regularly sewing the marginal portions of
the pair of overlapping circular fabrics; reversing the right and
wrong sides; and sewing the marginal portions of the reversed sides
so that the marginal end portions can be similarly hidden in the
inside of the air bag.
Such reversing serves to make the air bag look nice, but at the
same time, it not only complicates the sewing, but also makes it
difficult to fold the air bag so compact as to allow it to be
accommodated within a limited space provided at the center of the
steering wheel, because the edge portion of the reversed air bag
becomes bulky.
The invention has been made in view of the above circumstances.
Accordingly, an object of the invention is to provide an air bag
whose volume as folded is so compact as to allow it to be
accommodated in place without involving the reversing operation or
losing its aesthetic appearance.
SUMMARY OF THE INVENTION
To achieve the above object, the invention is applied to an air bag
in which a pair of circular fabrics overlap one upon the other and
their marginal portions are stitched by crossing a sewing thread or
sewing threads on the side of their edges to form a seam so that
the seam is showing.
Although the seam is showing and the sewn fabrics are not reversed,
the marginal portions are stitched with the sewing thread(s) in
such a manner that the sewing thread(s) crosses at their edges.
Therefore, the marginal end portions are neatly enwrapped,
providing the air bag with an unimpaired appearance. In addition,
the absence of the reversing allows the volume of the air bag as
folded to be reduced, thereby making the air bag compact.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a bottom view of an embodiment of an air bag according to
the present invention;
FIG. 2 is a sectional view taken along a line II--II shown in FIG.
1;
FIG. 3 is a top view of the embodiment;
FIG. 4 is an enlarged sectional view taken along a line IV--IV
shown in FIG. 1;
FIG. 5 is a development view in which a seam of marginal portions
of the air bag is developed on a plane with the edge E as the
center;
FIG. 6 is an enlarged sectional view showing another air bag in
terms of a portion corresponding to that shown in FIG. 4;
FIG. 7 is a development view showing the air bag in FIG. 6 in terms
of a portion corresponding to that shown in FIG. 5; and
FIG. 8 is an air bag mounted on a motor vehicle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 to 4 show an air bag B, which is an embodiment of the
invention.
The air bag B consists of an upper fabric 1a and a lower fabric 1b.
These fabrics 1a, 1b are formed of an elastic woven fabric such as
nylon or polyester, one surface thereof being coated with rubber,
resin, or the like, and are cut in a circular form. The upper
fabric 1a has no special holes, while the lower fabric 1b is
provided with an opening 2 to allow a pressurized gas generator to
be mounted in the middle thereof. On both sides of the opening 2
are gas-discharging holes 3. The opening 2 and the gas-discharging
holes 3 have patches 4, 5 applied to the wrong side and regularly
sewn by a sewing thread 6. Reference numeral 7 designates
bolt-inserting holes for fixing the pressurized gas generator.
The pair of fabrics 1a, 1b overlap one upon the other and are
stitched with sewing threads 8, 9 in the interlocking form at their
overlapping marginal portions. The sewing thread 8 is used to sew
inner marginal portions in two lines of stitching, while the sewing
thread 9 is used to stitch the outer marginal portions at a
predetermined pitch so that it crosses at the edge E. The thus sewn
marginal end portions are not hidden in the inside by reversing the
pair of fabrics as in the conventional air bag, but remain exposed.
However, owing to the stitching by the sewing thread 9 which
enwraps the edge E from outside, its appearance is not impaired at
all.
As shown in FIGS. 4 and 5, the sewing thread 9 is arranged
separately for each of the fabrics 1a, 1b. These sewing threads 9,
9 are used to stitch the marginal end portions by interlacing
themselves at the edge E. Reference numeral 9' designates a sewing
thread for catching such stitched threads 9, 9.
The sewing thread 9 is not necessarily arranged separately on each
of the fabrics 1a, 1b as in the above embodiment, but may be
arranged so that a single piece of sewing thread 9 is used to
stitch the marginal portions in such a manner as to alternately
spread over both fabrics 1a, 1b as shown in FIGS. 6 and 7.
In an embodiment shown in FIG. 6, the marginal end portions of both
fabrics 1a, 1b are folded back inwardly together and stitched as
folded by the sewing thread 9. The stitching with the marginal end
portions folded back, or hemstitching, contributes to further
catching the sewing of the outer peripheral portions.
The thus constructed air bag has its seam exposed and has its pair
of fabrics 1a, 1b not reversed. Therefore, the reversing process
after the sewing can be dispensed with, thereby simplifying its
overall sewing process. In addition, the pair of fabrics can be cut
circularly and sewn simultaneously by an interlock sewing machine
with the marginal portions thereof being cut roughly, thereby
allowing the sewing process to be shortened significantly. Absence
of the reversing of the fabrics contributes to reducing the volume
of the air bag as folded, thereby allowing the folded air bag to be
compact for accommodation in the steering wheel.
Further, although the air bag does not have the pair of fabrics 1a,
1b reversed after having them joined by stitching the marginal
portions, the edge where the marginal portions meet is stitched by
the sewing thread, and this neatly enwraps the marginal end
portions, thereby preventing the appearance of the air bag from
being impaired.
As described in the foregoing, according to the air bag of the
invention, the seam is not reversed and is left exposed. Therefore,
the conventional process of reversing can be dispensed with,
thereby contributing to simplifying the overall sewing process. In
addition, the nonreversing of the seam of the fabrics reduces the
volume of the air bag as folded, thereby allowing the air bag to be
compact. Further, the marginal portions of the fabrics are stitched
with the sewing thread(s) so that the sewing thread(s) crosses at
the edge, thereby allowing the marginal end portions to be
enwrapped neatly. Thus, the nonreversing of the fabrics does not
lead to impairment of the appearance of the air bag.
Moreover, the air bag can be sewn simultaneously with cutting,
thereby contributing to simplifying its sewing process as well.
* * * * *